10 things you need to know before the opening bell

Here is what you need to know.

Chinese stocks get slammed as traders return to work. China's Shanghai Composite plunged 3.72% as traders returned to work following the week-long National Day holiday.

The Bank of China makes a move to bolster growth. Monday's sell-off came after China's central bank announced it was cutting its reserve requirement ratio for some lenders by one percentage point, releasing 1.2 trillion yuan ($175 billion) into its financial system.

The first round of Brazil's presidential election is in the books. Far-right Congressman Jair Bolsonaro took 46.3% of the vote and will face off against leftist Fernando Haddad, who won 29%, in the second round on October 28, Reuters says.

Saudi Arabia still has plans for an Aramco IPO. "I believe late 2020, early 2021," Saudi Crown Prince Mohammed bin Salman told Bloomberg. "The investor will decide the price on the day. I believe it will be above $2 trillion. Because it will be huge."

Iran's oil exports drop further. Oil shipments out of Iran fell to 1.1 million barrels per day in September - down from at least 2.5 million barrels per day in April - as a result of President Donald Trump's sanctions against the republic, Reuters says, citing Refinitiv Eikon data.

Paul Romer and William Nordhaus win the 2018 Nobel Prize in economics. Romer was awarded for his work on the integration of technology into forecasting, while Nordhaus received the prize for looking at climate change in economic modeling.

Tech stocks have an ominous resemblance to the dotcom-bubble era. Strategists at Morgan Stanley Wealth Management compared the last five years of this bull market to the dotcom bubble and observed a number of striking similarities.

The world's biggest stock bear predicts 'immediate and severe consequences' for the record-setting market. John Hussman, the outspoken investor and former professor who has been predicting a stock crash, says the Federal Reserve is largely to blame for a toxic situation in markets and predicts an imminent crash will wipe out $20 trillion worth of stock-market value.

Apple says it found no signs of hacking. In a letter to Congress, George Stathakopoulos, Apple's vice president for information security, said there was no evidence chips inside servers sold by Super Micro Computer allowed for backdoor transmissions to China, Reuters reports.

The US Treasury market is closed. The bond market is closed in observance of Columbus Day.